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Model 3 may have Solar Roof that can charge the vehicle

Discussion in 'Model 3' started by X-Auto, Nov 25, 2016.

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  1. Garlan Garner

    Garlan Garner Supporting Member

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    I know that not everyone has access to services such as Uber, however I would have to agree with you. I would find use a friend or use an ICE car to park for a long trip.
     
  2. Model 3

    Model 3 Active Member

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    Surprise, there is someone that will just have one car, and can't just find "an ICE car" to use when they find that they really should have ordered the solar panel with their BEV ;)
     
  3. Garlan Garner

    Garlan Garner Supporting Member

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    #103 Garlan Garner, Dec 4, 2016
    Last edited: Dec 4, 2016
    The problem that I see is that many people have HIGHLY overrated perception of the output and performance of solar.
    You need a lot of square footage to produce some notable solar output as it would pertain the capacity of a Tesla. There just isn't enough space on the roof of a Tesla to produce any notable kWh's. See my solar progress per panel below in my signature.

    Secondly - Do you realize how many failure ( service center ) points that would be added to the mass produced M3?

    There are people who already park their Teslas for long periods at the airport. So its obviously not necessary to have a solar roof. The person who made the post says - that they are parking at the airport for long periods of time...so..... Its happening without the option of ordering the solar panel roof....and obviously - aren't' getting stranded....sooo...... I'm not sure what they want.

    Again it would take over a month to get a 10% charge on a 100D - as long as the car was facing 33 degrees directly directly into the sun all day - in the summer time in Chicago where the days are the longest.
    Again the 100D only depletes 2.7% in a month during the same time frame at the same time of the year. And only depletes 10.7% during a month in the winter.
    So you mean I would lose 27 miles out of 270 miles in a month? I would still have approx. 240 miles left? Where in the US can you be where in 240 or even 180 miles you can't get to a Tesla SC?
    No thanks on the solar roof.....I would rather have my panoramic roof view.

    Tesla is the only Car maker that we can have this discussion about because nothing currently compares to the range of a Tesla. If a Tesla can't do it, don't EV it.

    If you know that 200+ miles is'nt enough distance for your needs...then don't make your only car an EV.
     
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  4. Model 3

    Model 3 Active Member

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    Hmm... I thought we was only talking about avoiding vampire loss, not adding any capacity to the main battery pack.

    Here you are only speculating. Maybe you are right, maybe not...


    But how much does it depletes you 12v battery? The 12v battery and the DC2DC converter that feeds it has from what I have seen been a big point for fails on the Model S.
     
  5. Dan Detweiler

    Dan Detweiler Active Member

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    Not relevant yet but this is another huge advantage to the automated driving aspect that Tesla is so far ahead of everyone else on. You won't have to park your car at the airport for two weeks for a long trip. Drive to the airport, have it drop you off, then send it home and it automatically pulls into it's nice warm safe garage and then plugs itself back in. Come home from the trip, summon the car and it picks you up at the curb. Pretty amazing stuff that will make all of these arguments irrelevant.

    Granted, this won't be available for a while but for me, I would rather the cost of implementing the solar roof go to quicker adoption of this level of automation. Again, that's just me.

    Dan
     
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  6. brucet999

    brucet999 Active Member

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    The traction battery recharges the 12V battery as it is. Failure of 12V batteries is not due to lack of charging, but due to damage from multiple charge cycles in a lead/acid chemistry.
     
  7. BluestarE3

    BluestarE3 Active Member

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    One can pay for a lot of taxi, Uber or shuttle rides for the added cost of a solar roof. ;) Some think it's a costly gimmick whereas others simply like the idea of having such a device and don't need to justify it (just as one doesn't need to justify fancy wheels or special paint job). However, there may be some who hear "solar panel" and assume it will do more than it's physically capable of doing (just as some hear "Autopilot" and mistakenly assume it means "autonomous") and will be disappointed and complain loudly that they've been cheated. That said, people are free to choose what they want, but none of us here have any direct influence on whether or not Tesla will even offer such an option.
     
  8. gregd

    gregd Active Member

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    Anybody have a comparison of the miles-per-day-just-sitting-there range reduction of the other EVs on the market? Just curious...

    My Roadster 2.0 seems to lose about a mile/day, more or less.
     
  9. ohmman

    ohmman Maximum Plaid Member

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    Both of my vehicles (Teslas), in energy savings mode, drop somewhere around 3 miles per day rated range. On a recent 7 day trip, my Model S expended about 24 miles of range while parked at the airport.
     
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  10. Zoomit

    Zoomit Active Member

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    By my math you'd need about 10 sq ft (0.9 m^2) of PV cells to counteract that daily loss. That's about the roof area between the forward and aft crossmembers above the driver on the Model 3.
     
  11. Electroman

    Electroman Well-Known Member

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    With that sq footage on your car roof, how many hours of uninterrupted sunshine do you need at what angle ?

    All of those conditions should be met to even get the minimum benefit of reducIng vampire loss.

    Unfortunately vampire loss is the most and impacts the most in cold winter months - which is exactly the season you don't see much sunshine either. Double whammy.

    As someone said like 21" wheels, this is another eye candy we can do without.
     
  12. Zoomit

    Zoomit Active Member

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    It was quick math, but I assumed 5 sun-hours, which I think is reasonable for a horizontal surface in many parts of the US. I did not include any inverter or charging losses.
     
  13. brucet999

    brucet999 Active Member

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    To offset vampire loss of 24 miles range in 7 days, under ideal conditions (parked on a 23º south-facing slope getting 6 hours useable sunlight a day) would require a 200W solar panel on the roof. Not likely.
     
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  14. omgwtfbyobbq

    omgwtfbyobbq Active Member

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    Tents are always an option, but climate control is nice to have too! I guess another use would be sleeping in the car in places where I couldn't set up a tent. It'd be nice to have during a power outage if it could be used as an off-grid inverter, ala the Prius. ~3-4kWh/day from PV panels on a car isn't a whole lot, but it's better than nothing.

    Running Our House on Prius Power
     
  15. omgwtfbyobbq

    omgwtfbyobbq Active Member

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    That depends on the energy used I guess. The TVs use very little power, so I'm not super concerned about them. The pilot light on the water heater on the other hand, is a bit greedy. I'm planning on switching to solar/electric hot water once I put in solar panels.

    Pilot Lights are Evil | Do the Math
     
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  16. Troy

    Troy Active Member

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    I found this video interesting. Apparently, it generates 300 Watts using high-efficiency Sunpower solar cells. That's 50% more than the Karma Revero's 200 Watts.

     
  17. BluestarE3

    BluestarE3 Active Member

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    How does the car move underneath the Fresnel lens structure to follow the angle of the sun? Some kind of fixed or limited autonomous driving feature that synchronizes with the position of the sun? With the concentration of light and, potentially heat, will this make the car inordinately hot inside?
     
  18. Troy

    Troy Active Member

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    #118 Troy, Dec 4, 2016
    Last edited: Dec 4, 2016
    @BluestarE3, the canopy is an experimental idea they came up with to go beyond 300 Watts. That part is not important. The important part is, the solar cells alone generate 300 Watts and the Sunpower representative also talks in the video adding credibility to the 50% more power claim.

    In THIS video Bjorn loses 101 km typical range in 27 days. The P85 has 400 km typical range. If we assume 76,000 Wh usable capacity for the 85 kWh pack, his daily vampire loss would be 101*76,000/(400*27)= 711 Wh. That's less than 2.5 hours. Seems doable even in winter.

    The efficiency increase and price drop in solar cells mean solar car roofs are starting to make more sense.

    Fisker Karma: 125 Watts
    Karma Revero: 200 Watts
    Ford Cmax: 300 Watts
    Tesla Model 3: ...
     
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  19. brucet999

    brucet999 Active Member

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    It might be more effective to move the fresnel structure to track the sun.

    Heat might not be such a problem. With 20%+ of the solar energy being converted to electricity, and probably similar reflectivity to normal roof materials - glass or paint - the difference with 50% more light energy is likely to be slight. Most of the heat gain in a parked car is from insolation through the glass surfaces which make up more area than the roof. The fresnel area would be concentrated on the roof alone.
     
  20. Model 3

    Model 3 Active Member

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    I have heard about more then one example where this did not work as intended, and a failure of the recharging of the 12V battery from the traction battery has got the 12V battery too get to low, and be rendered unusable.


    True, and you may even pay even more for "a lot of taxi, Uber or shuttle rides" for the cost of the car - with or without a solar roof. And yes, this is one of the reasons that I did mentioned a few other scenarios there it may come handy, as "taxi, Uber or shuttle rides" or train etc. may be a viable solution for the airport, it is not a solution when I park for a few weeks "in the middle of nowhere" to go hiking, fishing, living at the cabin without electricity etc.


    That is on the other hand very true...
     

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